Electromechanical control systems



July 15, 1958 G. e. vr'r-r, JR

ELECTROMECHANICAL con'mor. SYSTEMS 2 Sheets-Sheet 1 Filed May 26, 1955 7.. T 3 FM V 5 m G M F fi J. w q u Z i q lllllll 1L BY flown July 15, :1958 G; \llTT, JR

' ELECTROMECHANICAL CONTROL-SYSTEMS 2 Sheets-Sheet 2 Filed May 26, 1955 w T RT 4 mm A W .l I I 2,842,774 3 V w 'EL'EC'IROMEYCHANICALCONTRO L SYSTEMS George'G. Vitt, J12, Grange, N. J., assignor to The Lionel Corporation, New York, N. Y., a corporation of New 'York v 7: v.

' "@Abbiicifibn May 26, 1955; Serial No; 511371 6 Claims. Chaim ,v lsrinvention relates to electromechanical control systems; and more specifically to -voi'ceiroperated' reversible motors for? controlling mechanical equipment as form- 1 staficefprosthetic devices such as=then1echanical hand-dis- .;c1o'sed .in ;U; patent: application of :Charles Gia'irn'o,

: filediMarchc23, 1954; Serial $10,418,033;- V '1' :While 'ithe'co'ntr'ol systemlin accordance withth'e in- ,vehtiont is. of general usefulness; it is partieularly' 'effec- "IiVfiE'fOI prostheticd'eviees of "the type" used to actuatean ar-tificial handjorthe firigers of the harid in instances nwhendwpersou, throughherve'dafiiage or other'causes "'hast 'lost 'rnuscular' control "of the fingers In the-above i irn'ntiolied' application 'the-' prosthetic deviceswere op- :er'ated by: switch rn'echanisms" responsive to air" pressure produced by theuser'through'a'siiecial r'riouthpiece sup- :fiorted onthebhest of the user anddisposedin the vi cin- I ftyfof thefliiou'thi This; inv'entiofovereo nes certainof 'fthe-liiiii'tatiohs'inhrent'in p erat'ed control and pr ovide's a 'co nbletely safe,"ea

tem" see pros-themdevices-mat wi1l e able independent rnechanica-l controls p I lajt''df as for "instance prosthetic" de viit'esf for e h hand 'a'n'd for'iudividuahfinger control to effect rnor'ep'relurality' of n""re si d es in e pro gapaa'ra a rlpo iandgtl rf'similaride '1) selective P r 'p ve'i ewvb a, t

hated". control ime ans"in1' accordance LIZ-ill rating the ft'humb'and s'ily, peia'te control sys- 1e fvelyillactm 1 prosth device it, the hand is denoted generally by the numeral '10. .Thisdevice is coupled by cables 11a to a "control' mechanism disposed within the box 12 This control mech'anisni is supplied with power snugly" about the neck of'the wearer by iiieans of a strap 7 17 or other suitableIsupporting means.

it will be bs rved-yin the illustrated prosthetic de-f vice-10, that 'the thuiir'1b"'of the wearerisflild' in relativelyf fixed position with respemoihe pal noftheha'nd "and that the index finger is moved bynieansof a series ofenc'ircling links or collars toward and away from the "thumb by mea'nsfof'pull cables 11', 11. In the operation "o'fthis device-which"will-be more completely described in connection with the circuit diagram of Figures 2a and 2b; the user sounds af substained tone; of predetermined fre'qiJeney afid this"tone i s 'detected' and converted'by tlie inicrophorie'1'5 'to an electric current for actuation tratdf insfic'h a nianner that it williacituate a relay wit-hrotate in onedir'ection. The sounding of thettone" a sec- 0nd time will cause the switch to rotate to an o "p "s'i'ti'on; When the tone'is sounded again the motor will I be" energized but this tinie it will move in a reverse direction. The soundingof the'tone a fourth" time will "iiiove theswitchirito an o position to complete the cycle In the case where two or more motors are tobe "selectively controlled to operate; for example, prosthetic d'evi'c es 'on'each hand; the control 'unit 12 is arranged to respond to atone of one'frequeney forthevojoeration of 'onernotor-and'to a. tone of"another frequency for the operation of the-second motor. From this itis' apparsel'ebiively operatedr i i i "Qhe "selectiveqcoiit'rol refe'rredflto above-is shown in Figures '24: and Zhand nchides' sthr ee essential elements "forrs'ing1e" eaa'linel e 'eraaah; nani'ely; an electronicamplifierfiilfia pe'vv'erjsti iu 21. and theelectrorneehanical g k power uansfcrmer zs and 24 having pri- "riiary wind1n I V I "i15 s 5re E6 'cte d in parallel and through a switch 27 I I lieicwer cable 13 and plug 14 for Connectionto asuitabIe po me effec or "line vo'u'age yarlatror'isf an *the' 'ogseiation 'of ft'his appaiatus a -veuage 're fila'toi'-fiil5 29 amseiies resistor 30 are connectedacross the supplyfvolta gje so as e iiiaimain azirior iiearly c n'staht lo'a'd' as'th'e power "'de in'and ofthe coritrol changes;

c c The'ktransforrnerTz luhas;ai -adjustable 0nd 7 y Sifin 7 order i'toiobtain secondarysivoltages' ranging efroin to hQi1t-116 volts; This transformer a's-zwill beishownipfo- .vide'sitheene'rgyjforr the"-uoperatiorrv ofr 'thejeontrol rnot'or iorming part of 1 theg electromechanical control devicefl}.

A Byt hc iadmstme tp ;"the; olta ef th e' control 'device; 12. This current is'arnplified andv willbe nioved; to an on"position causin' the motor to i t that a number of motors" or" control devices maybe Referring to the fpower supply th'ere are 2515551;za'respeeay ly; These windput is connected by means of the leads 33 and 34 to terminals 1 and 2 of the female cable connector 35.

The transformer 23 provides the voltages for the operation of the amplifier 20 and includes in this embodiment "three separate secondary windings 36, 37 and 38. The winding 36 is a high voltage secondary and has its outer terminals connected to the plates 39 and 40 of a full wave rectifier 41. The filament 42 of the rectifier 41 is heated by the secondary winding 37. This arrangement provides for full wave rectification with the positive lead 43 of the voltage supply being connected to the filament and the negative lead 44 being connected to the center tap of the winding 36. The voltage developed between the conductors 43 and 44 is filtered by a pair of con densers 45 and 46 and an intervening series connected filter choke 47. The output voltage appearing across the condenser 46 is stabilized by means of a resistor 48 in series with the positive conductor 43 and a voltage regu- "lator 49 bridging the conductor 50 connected to the output of resistor 48 and the negative conductor 44. This filtered voltage is now applied to the female connector 35 with the lead 50 being connected to terminal of that connector and the lead 44 to terminals 3 and 7 as illustrated.

The third winding 38 of the transformer 23 provides the filament voltage for the tubes within the amplifier 20 and in addition a rectified bias voltage. More specifically, the terminals of the winding 38 are connected by means of the leads 51 and 52 to the female plug 35 with the lead 51 being connected to terminal 6 thereof and the lead 52 being interconnected With the lead 44 and consequently terminals 3 and 7. If desired the lead 44 may be connected directly to ground. The negative bias voltage is produced by a pair of rectifiers 53 and 54 connected as a voltage doubler, a pair of condensers 55 and 56 and a load resistor 57. This produces a voltage of the order of volts on the output lead 58 which is connected to terminal 4 of the connector 35.

As previuosly discussed the invention provides means for the selective operation of a plurality of motors or other electromechanical apparatus. To attain this end an individual amplifier may be employed for each motor or in the alternative additional amplifiers 20 omitting the initial stage of amplification may be interconnected with the first amplifier at a point after the first stage of amplification as illustrated in the figure. Considering the illustrated embodiment of the invention the microphone i5 is connected by means of the cable 16 and a plug 60 to an input jack 61. The microphone 15 is preferably of the carbon button type and is connected by means of said jack between the cathode 61' of the first amplifier tube 62 and the ground conductor 63. The resistance of the microphone provides the bias for the tube 62 and its grid 63 is therefore connected directly to ground. The plate circuit of the plate 65 includes a series resistor 66 and the conductor 67 which connects to terminal 5 of a male cable connector 68. This male connector cooperates with terminal 5 of female connector 35 and in this way high voltage from the conductor 50 of the power supply is applied to the conductor 67 of the amplifier 20. The output of the first stage is taken from its plate 65 through a coupling condenser 69 as illus trated.

As mentioned above the initial stage of amplification just described may either form part of each amplifier 20 used for the selective operation of a number of motors or a single common stage may be employed for all amplifiers. In the latter case the output from the condenser 69 is fed through a series resistor 70 to the grid 71 of a pentode vacuum tube 72. If additional amplifiers .20 are used the condenser would also be connected through a lead 73 to additional series resistors 74 and 75 which correspond in other amplifiers to the resistance 70 of the illustrated amplifier 20.

The tube 72 is connected in a generally conventional manner, with the grid 71 being returned to ground through a resistor 76. The suppressor grid 77 and cathode 78 are connected to ground through a resistor 79 and condenser 30 to provide bias for the grid 71. The screen grid is connected through a resistor 82 and lead 83 to the high voltage conductor 67 and is also bypassed to ground by a condenser 34. The plate 85 is connected to the high voltage conductor 67 through a resistor 86 and the output is taken from the plate 35 through a concondenser 87 to conductor 96.

In order to provide frequency selectivity for each amplifier 20 the tube 72 is provided with a feedback circuit including a band rejection filter that will limit the operation of the amplifier to a relatively narrow pass band of about twenty cycles. This is attained by means of a twin T filter connected to conductor 96 and including three condensers 88, 89 and 90 and three resistors 91, 92 and 93. The condensers 88 and 89 are connected in series one with the other and the resistors 91 and 92 are similarly connected. The outer terminals of resistor 91 and condenser 88 are connected to the output side of the coupling condenser 87 While the outer terminals of the condenser 89 and resistor 92 are connected through a coupling condenser 94 and the lead 95 to the grid 71 of the tube 72. This provides a feedback circuit from the plate 85 to the grid 71. The junction between condensers 83 and 89 is connected to the ground conductor 63 through the resistor 93 while the junction between resistors 91 and 92 is connected through condenser 90 to the ground conductor 63. This double T filter functions as a narrow band rejection filter in that the filter has a very high impedance over a narrow selected range of frequencies so that little voltage is fed back to the grid and consequently a relatively large signal appears at the plate 85. At all other frequencies the impedance of the filter is relatively low and presents a large feedback signal to the grid 71 and maintains the signal at the plate 85 at a very low level.

The output signal from the condenser 87 is fed through the conductors 96 and 97 to the grid 98 of the tube 99. The plate 100 of this tube is connected to the conductor 67 while the cathode 104 is connected through a pair of resistors 101 and 102 to the ground conductor 63. The grid 98 is returned through a resistor 103 to the center tap of resistors 101 and 102. The tube 99 in this way functions as a cathode follower amplifier and the output is obtained from the cathode 104 through a coupling condenser 105. The signal appearing at output side of the condenser 105 is an A. C. signal and is transformed into a D. C. signal by its rectifier 106 and resistors 107 and 108. In addition a negative bias is applied by means of terminal 4 of cable connector 68 and lead 108 to the bottom side of resistors 107 and 108. A rectified output signal from the positive side of the rectifier is connected through the conductors 109 and 110 to the grid 111 of tube 112. The cathode 113 is connected directly to ground While the plate 114 is connected through the coil 115 of relay 116 to the positive conductor 67. The bias provided by conductor 108 in effect biases the grid of the tube 112 negatively so that it does not draw current. When a signal is impressed on the condenser 105 it is rectified and upon exceeding the value of the negative bias it will swing the grid 111 positively and cause it to conduct curent whereupon the relay coil 115 will be energized to actuate the movable contact 117 of the relay and cause it to touch the fixed contact 118. It will also be observed in this connection that the grid 111 of the tube 112 is provided with a condenser 119 between the grid and conductor 63. This condenser together with the resistor 107 forms an RC network having a time constant that is a function of the values of these components and is preferably made long enough so that when the tube 112 conducts current by reason of the application of a positive voltage or a less negative voltage P 1' neednot continue. the voice vsignaL-aftler helhasjcalised the relay to" function. ..It;.isi also .toibe observed. that 7',

- the utilization .ofa. negative. bias'aon'sthe grid .111 [and .the condenser 119,.producejs a delayed action jso that the tone 'thatis. sounded for .operation i of the relaygmust be. sustained for. a. predetermined; length of time. qhefore sufiicientrvoltagewill.bedewloPe and relay 116.. j ,In.,this ,way, punds such as those obtained by knscrihgane'm r'ophon or produced by nor l speech "will (not; t ion: to operate *the relay i 16. Thus "the entire device is'i ifnrhune :te rat-ma noise or signals and is at all time under the completeandtpositive control of the operator. v

The electromagnetic apparatus 22 operated by the relay 16 includes a drum type reversing switch 120 having ring contacts 121 and 122 on the ends thereof and four elongated contact members 123 spaced at about 90 degrees .one from the other with alternate contacts connected to nected through conductors 129 and 130 to the ground lead 63 of the amplifier 20 which in turn is connected to the contact 3 of the male connector 68. The top side i of the plunger magnet coil 127 is connected through lead 130' to the junction of leads 129 and 130 while the lower terminal of this coil is connected to the ring 121 ofthe rotary switch 120 and through a conductor 131 to terminal 2 of the male connector 68. It will be observed that when the relay contacts 117 and 118 are closed voltage will be applied to the plunger magnet 127 which will then actuate the pawl and ratchet to rotate the drum switch 120, 45.

The armature of motor 132 is connected through commutator brushes 133 and 134 to brushes 135 and 136 *which ride on the surface of the drum. These brushes are positioned relative to the elongated terminal members -123 so that as the drum is rotated 45 degrees the brushes.

135 and 136 will first contact adjoining terminal members 123 and upon subsequent increments of rotation will'rest upon the insulating material between the contacts 123 and then the next successive pairs of "members 123 etc. In this way the flow of current through the brushes 133 and 134 will be successively interrupted and reversed. To complete the motor circuit the ring 122 on the drum switch 120 is connected by a conductor 137 to one terminal of the field 138 the motor 132 and other terminal of the field is then connected through a conductor 139 to the lead 130'. Thus the energy for operating of the motor is obtained from the rectified supply of transformer- 24 and its operation is completely under control of ,the

drum switch 120.

'With the apparatus as describedabove when the operator sounds a tone in his throat of a selected frequency for a predetermined interval, he will cause the relay 116 in the amplifier 20, responsive to that frequencyflooperate and this in turn will cause the motor 132 to be operated in one'direction. The motor will continue, to

' operate even after the relay116 is deenergized. To stop the motor the same signal is given a second'time. This functions to close the relay 116 and operate the plunger magnet 126 which through action of the drum switch 120 interrupts the armature circuit of the motor v132. To reverse the operation of the motor he sounds the signal a third time to actuate the relay 116 and plunger magnet I 126. This completes the motor armature circuit but in dto operate the. lube.. 112-.

tion of additional amplifiers connected with the resistors 74 and 75 additional electromagnetic units such as unit 22 may be selectively operated. In practice it has been found that in a case wherein three such electromagnetic units 23 are to'be employed that frequencies of the order of 220 cycles, 280 cycles and 330 cycles can-be r'eproshown and described it is apparent that transitions and 7 other similar devices may be used to increase portability and that further modifications, alterations and changes may be made without departing from the true scope and spirit thereof.

What is claimed is: i a

1. An electronic control for prosthetic devices com prising a microphone, an amplifier including a filter for limiting the response of said amplifier toa predetermined j frequency range, means for rectifying the output signal of said amplifier, a second amplifier responsiveto said rectified output signal, means including a time delay network for negatively biasing said second amplifier, a relay including at least two cooperating contacts and respon .sive to the last said amplifier, and electromagnetic means operable in response to said relay for actuating said prosthetic device. a

2. An electronic control for prosthetic devices according to claim 1 wherein said electromagnetic means in cludes a mot-or and an electromagnetically operated reversing switch connected with said relay and saidmotor.

3. Voice operated apparatus comprising a microphone,

an amplifier connected with said microphone a band pass filter for limiting the response of said amplifier to a predetermined frequency band width, means for rectifying the filtered signal, means including a relay actuated by.

the rectified signal and means in circuit with said rectifier for delaying operation of said relay until the signal is sustained for a predetermined period and for holding said relay in the actuated position for a predetermined interval after removal of said sustained rectified signal.

as an amplifier, a feedback circuit between the input and output of said tube and a band rejection filter in' said feedback circuit.

5. In voice operated apparatus,.a vacuum tube hav ing a cathode, grid and plate, means for applying a voltage between the plate and cathode of said tube, a carbon microphone connected in' series with the cathode of said tube, at least one amplifier responsive to the signal produced by said tube and including a filterfor limiting the frequency'of the. output signal of said amplifier to a predetermined narrow frequency range, a rectifier for rectifying said output signal, a second amplifier includ- 6. A voice operated electronic control for prosthetic devices comprising a vacuum tube amplifier having-a j the reverse direction and causes the motor to run in a cathode circuit, a carbon microphone in series with said 4. Voice operated apparatus according to claim 3 V wherein said filter comprises a vacuumt-ube connected 7 cathode circuit, and at least one frequency selective con- References Cited in the file of this patent trol means coupled with said amplifier including a second UNITED STATES PATENTS vacuum tube amplifier having a frequency selective feedback circuit, means for rectifying the output of said 2173426 Scott Sept 1939 second amplifier, a third amplifier including negatively 5 2321963 Case et 1940 biased time delay means to delay the response thereof to 24115O1 Brubaker 1946 both positive and negative changes in the rectified signal, 2509345 Howell et May 1950 a relay connected with the last said amplifier and respon- 25 42189 Gates et a1 1951 sive to the signal produced thereby, a magnetically op- 2567066 Goldman Sept 1951 erated rotary reversing switch actuated by said relay and 10 2679649 Alderson June 1954 a reversible motor connected to said switch. OTHER REFERENCES The Radio Amateurs Handbook, 29th ed., 1952, pp. 445 and 447 cited. A copy is in the Patent Office Scien- 15 tific Library. 

